Headphones for £100 or under

[vopos]

I was planning on buying the AKG K550's but I don't think they'll be the best headphones for me. I will use the headphones outside as well as inside and with the headphones I'll watch films and youtube videos and listen to dubstep, classical and rock music. The headphones build quality and sound quality is important to me so which headphones should I buy? (I was considering the V-Moda crossfade LPs, but then I saw this http://www.whathifi.com/v-moda/crossfade-lp/review  )

 

Note: I would like a natural sound with a decent sound stage with not too much badd

[Goldilock]

crossfade is bassy headphone, M40X is generally natural sounding.

[vopos]

are the m40x's better than the akg k550?

and what about the m50xs?

[2FOX]

I use ATH m50 and it is gr8. So M50x should be similar or better!